1. Field of the Invention
The present invention relates to a stake, bunk and bunk pocket used to constrain logs on the bed of a truck or trailer.
2. Description of the Background Art
Most logging trucks or trailers have for many years used different materials for supporting the logs on top of the bed of the vehicles during the transportation of freight. In the beginning, wood was used for the stake materials which are vertically extending posts which fit into lateral fixtures. These lateral fixtures are referred to as bunks. Each bunk has an opening in both ends referred to as a bunk pocket. The bunks are spaced along the length of the vehicle, and the bunk pockets are sized to match the stakes which fit vertically into the bunk. Federal regulations specify that stakes must have a specific yield strength, making wood stakes obsolete.
The prior art has focused on methods of extending the stakes as in U.S. Pat. Nos. 3,811,724, 4,668,000, 3,712,639 and 5,611,286. These patents focused on extending the height of the stakes using mechanical or hydraulics methods, and did not focus on the unique properties of the materials used to create the stake. Stakes are normally used to constrain high or low density logs on logging trucks or trailers. The density of the logs determine the length of the stake. The type of stake today is typically steel, with some stakes being telescoping. Depending on the density of the logs and the quantity of logs, stakes may need to be changed to longer or shorter ones on a given load so they conform to federal safety standards and still offer the maximum load carrying capacity.
Logging companies prefer to place the maximum load on each truck or trailer to maximize the cost effectiveness of each load. Typically trucks or trailers have had to replace the existing stakes with new stakes of greater height or strength depending on whether they are carrying high or low density logs. Working and moving steel stakes is difficult because of their weight and operators must get up on the bed of the vehicle to reposition the stakes. When the truck or trailer has not met the maximum weight limit based on load restrictions, some steel stakes can be extended either manually or automatically to increase or decrease the load capacity.
Typically steel and wood have had to be extremely heavy to provide the necessary strength to constrain the load. This cuts down on actual deliverable cargo since the weight of the stakes displaces some of the deliverable cargo. Heavy, bulky stakes are difficult to manage or control and create a more hazardous condition for workers adding to the total cost of hauling logs due to injuries and lost time. Normally, aluminum or other lightweight metals do not have the strength to support the heavy loads inherent in the logging industry.